Abstract 113: Chemerin Regulates Adipocyte Size in Mesenteric Perivascular Adipose Tissue When on a Normal but Not High Fat Isocaloric Diet

Abstract

Chemerin is an adipokine, positively associated with blood pressure, and used as a marker for metabolic syndrome. We hypothesized that a global knockout (KO) of chemerin in the rat would lead to a global decrease in white visceral fat mass in both control (C) and high-fat (HF) diets. Wild-type (WT) and KO rats on a Sprague-Dawley background were fed a C (10% kcal fat) or HF (60% kcal fat) diet with weekly monitoring of body weight and food consumption. MicroCT was performed at 8 weeks and 25 weeks of age to measure subcutaneous and intrabdominal fat. Blood pressure was measured by radiotelemetry measuring for 10 seconds every 10 minutes for 24 hours/day. At the end of 25 weeks, fats were dissected and flash frozen for PCR analysis or fixed with paraformaldehyde for histology. There were no physiologically relevant differences in blood pressure (table). Within each diet, there were no significant differences in final total body weight (table). KO-C had reduced intrabdominal fat when compared to WT-C. Histology of the KO-C intrabdominal white fat components revealed a significant leftward shift in mesenteric adipocyte area compared to WT-C (table; p = 0.01 by the Kolmogorov-Smirnov test) but no changes in retroperitoneal adipocytes. RNA expression of perilipin, adiponectin, and fatty acid synthase normalized to beta-2 microglobulin were all undetectable only in the mesenteric fat, not retroperitoneal fat, of KO-C animals compared to WT-C (table). These data are the first to provide in vivo support for the role of chemerin in adipogenesis but also indicates that chemerin’s role in adipocyte development specific to a location vital for blood pressure regulation.